Patricia S. Choban

Enoxaparin for Thromboprophylaxis in Morbidly Obese Patients Undergoing Bariatric Surgery: Findings of the Prophylaxis Against VTE Outcomes in Bariatric Surgery Patients Receiving Enoxaparin (PROBE) Study

Background: Obese patients undergoing bariatric surgery are at significant risk for venous thromboembolism (VTE). We performed a multicenter, retrospective survey to evaluate the safety and efficacy of enoxaparin for thromboprophylaxis in patients with morbid obesity undergoing primary bariatric surgery. Methods: From January to December 2002, 668 patients who underwent primary bariatric surgery at 5 centers were analyzed retrospectively. Baseline patient demographics, objectively diagnosed cases of VTE, and bleeding events were recorded. Patients received enoxaparin preoperatively (30 mg) or postoperatively (40 mg) every 12 or 24 hours or upon discharge (30 mg every 24 hours for 10 days). Results: Overall, there were 6 (0.9%) pulmonary embolisms (PE) and 1 (0.1%) occurrence of deep vein thrombosis (DVT); all but 1 occurred after the cessation of thromboprophylaxis. The highest incidence of VTE was at Center B, which did not administer perioperative thromboprophylaxis (1 DVT and 2 PEs). There were 6 (0.9%) severe bleeding complications: 3 at center D and 3 at center E. In Center B, 2 deaths were recorded (0.3%): 1 due to sepsis and 1 due to bleeding, with both occurring after thromboprophylaxis was discontinued. Conclusion: The administration of enoxaparin, in various dosing regimens, is safe for thromboprophylaxis in morbidly obese patients undergoing bariatric surgery. Fewer events occurred with perioperative prophylaxis initiated in the hospital. Because all thromboembolic events occurred after the cessation of thromboprophylaxis, extended thromboprophylaxis may be of value.

Changes in patients' taste acuity after Roux-en-Y gastric bypass for clinically severe obesity.

OBJECTIVE Patients who have undergone Roux-en-Y gastric bypass (RYGB) for clinically severe obesity often report an aversion to sweet foods and meat. This study was designed to determine whether changes in taste acuity occur after RYGB. DESIGN This prospective, repeated measures trial evaluated acuity for sweet (sucrose) and bitter (urea) tastes, zinc status, and reported changes in taste perceptions in patients undergoing RYGB for weight reduction. SUBJECTS Taste acuity and serum zinc level were measured in 14 subjects, 6 men and 8 women (mean preoperative body mass index [calculated as kg/m2] = 60.8 +/- 11.8 and mean age = 38.4 +/- 6 years), before surgery and 6 and 12 weeks after surgery. Inquiries regarding taste preferences were made at each postoperative visit with specific reference to sweets and meat. Serum zinc level was measured at the same visit. A noncontrolled comparison group of 4 subjects who were consuming a very-low-calorie diet also underwent taste acuity testing at similar intervals. MAIN OUTCOME MEASURES The main outcome measures were recognition taste thresholds, serum zinc levels, and taste preference changes. STATISTICAL ANALYSIS Analysis of variance with repeated measures over time, Pearson correlation coefficients, and post hoc analysis of variance were used to analyze data. RESULTS Mean recognition thresholds for sucrose were 0.047 +/- 0.03 mol/L preoperatively and fell significantly to 0.024 +/- 0.01 and 0.019 +/- 0.01 mol/L at 6 and 12 weeks postoperatively, respectively. Overall, there were no significant differences in taste thresholds for urea over time; a significant difference was noted, however, in the pattern of change for urea between patients who reported an aversion to meats and those who did not. Zinc concentrations did not change during the study. APPLICATION/CONCLUSIONS At 6 weeks postoperatively, all patients reported that foods tasted sweeter, and they modified food selection accordingly. Six patients reported an aversion to meats associated with increased nausea and vomiting. Acuity for sweet and bitter tastes may need to be considered when planning dietary modifications for patients undergoing RYGB.

Efficacy of Hypocaloric Total Parenteral Nutrition in Hospitalized Obese Patients: A Prospective, Double-Blind Randomized Trial

Obesity is a major health problem in the United States today. Traditionally, management of obese hospitalized patients has not differed from that of normal-weight patients, with calorie and protein needs based on current body weight and weight loss postponed until the acute illness has subsided. This study was undertaken to determine whether obese hospitalized patients (> 130% ideal body weight) requiring total parenteral nutrition and given hypocaloric (HC) feedings with adequate protein intake could achieve nitrogen balance comparable with that of controls (C) given isonitrogenous normocaloric formulas. Sixteen obese patients (HC = 9, C = 7) were randomized to either HC (50% resting metabolic energy expenditure, plus protein; calories:nitrogen = 75:1) or C (100% resting metabolic energy expenditure, plus protein; calories:nitrogen = 150:1) formulas. Resting metabolic energy expenditure was determined by indirect calorimetry on day 0 and weekly, and nitrogen balance was determined daily. The two groups were similar in Harris-Benedict predicted energy expenditure and metabolic energy expenditure, initial and final serum albumin, total iron-binding capacity, and weight loss. Total daily calorie and nonprotein calorie intake per kilogram body weight were 14 +/- 4.1 (HC) vs 25 +/- 4 (C) and 7 +/- 1.9 (HC) vs 20 +/- 3 (C), respectively. Protein intake was 1.23 +/- 0.4 (HC) vs 1.31 +/- 0.2 (C) g/kg per day. Initial respiratory quotients were similar and consistent with fasting (HC = 0.7 +/- 0.09 vs C = 0.66 +/- 0.09); final respiratory quotients in C patients reflected mixed fuel use (C = 0.82 +/- 0.11 vs HC = 0.7 +/- 0.12).(ABSTRACT TRUNCATED AT 250 WORDS)

The Effect of Roux Limb Lengths on Outcome after Roux-en-Y Gastric Bypass: A Prospective, Randomized Clinical Trial

Background:The effect of limb-length on weight loss after Roux-en-Y gastric bypass (RYGBP) is controversial; hence, the optimal limb-lengths have not been determined. This study evaluated the effect of different limb-lengths on weight loss after RYGBP. Methods:The study was a prospective randomized clinical trial in which patients undergoing RYGBP (110 F,24 M; mean age 39.7) were randomized as follows: BMI ≤ 50 (N=69): A-75 cm (N=35) vs B-150 cm alimentary limb (N=34) and C-150 cm (N=33) vs D250 cm alimentary limb (N=31). All other aspects of the operation were identical. Patients were followed at 2 weeks, 6 weeks, 6 months, 12 months, 18 months, 24 months and yearly thereafter. Results: There were no significant differences in age, sex, race, initial BMI, or excess weight between patients assigned to groups A vs B and C vs D. Postoperative nutritional intake was also similar between groups. Within each weight category, there were no differences in mean weight loss, change in BMI, and % excess weight lost (EWL) over time. When the number of patients achieving 50% EWL was evaluated, there was no difference between groups with a BMI ≤ 50 kg/m2; however, among patients with a BMI >50 kg/m2, a significantly greater percentage of those having a 250-cm limb achieved >50% EWL at 18 months postoperatively.This difference was lost at 24 and 36 months, possibly due to the small sample size. Conclusions: In patients with a BMI ≤ 50, there appears to be no advantage to longer limb-lengths. In patients with BMI >50, however, these data suggest that longer alimentary limb-lengths may be associated with a higher percent of patients achieving >50% EWL. Longer follow-up studies of the effects of limb-length on success of RYGBP are indicated.

Changes in measured resting energy expenditure after Roux-en-Y gastric bypass for clinically severe obesity☆

BACKGROUND Roux-en-Y gastric bypass (RYGB) results in sustained weight loss and amelioration of comorbid conditions in patients with clinically severe obesity. The mechanism of weight loss after RYGB is not well defined. The objective of this study was to document the changes in measured resting energy expenditure (MREE) over time in patients with clinically severe obesity after RYGB. METHODS We prospectively studied MREE in 70 patients (11 male, 59 female; body mass index [BMI], 40 to 80 kg/m2) treated by RYGB. MREE was measured by indirect calorimetry before operation and at 6 weeks and 3, 6, 12, 18, and 24 months after operation. Patients were stratified to hypometabolic ([HM] MREE less than 85% of Harris-Benedict [HB] predicted; n = 22) or normal metabolic rate ([NM] MREE +/- 15% HB predicted; n = 48) before operation; mean BMIs were HM, 53.4 +/- 11.0 kg/m2; NM, 51.4 +/- 9.8 kg/m2; p = not significant. MREE, weight loss, percent excess body weight loss (EWL), and energy intake were determined at each time point. RESULTS Overall, MREE was significantly less than HB-predicted REE before operation (90 +/- 28%), but rose to become equal to the HB-predicted REE by 6 weeks (96 +/- 15%) and remained so. When stratified by initial metabolic rate, MREE increased significantly in the HM patients by 6 weeks, from 1329 +/- 604 kcal/day (55% of HB predicted) to 1882 +/- 398 kcal/day (88% of HB predicted) (p < 0.001), and MREE remained normal (2332 +/- 484 kcal/day to 2029 +/- 410 kcal/day) in the NM patients. Percent EWL was similar in both groups at each time. Energy intake was 2603 +/- 982 kcal/day before operation and fell to 815 +/- 196 kcal/day at 3 months, 969 +/- 241 kcal/day at 6 months, 1095 +/- 307 kcal/day at 12 months, 1259 +/- 466 kcal/day at 18 months, and 1373 +/- 620 kcal/day at 24 months, and was similar between the groups at each time point. Percent HB-predicted REE increased significantly after operation despite a significant decrease in energy intake. CONCLUSIONS RYGB is associated with significant changes in MREE over time. In NM patients MREE fell over time consistent with weight loss but remained normal, whereas patients who were hypometabolic exhibited increases in MREE toward normal. These changes in MREE occurred despite reduced energy intake comparable to a very low calorie diet. This paradoxical effect on MREE may contribute to the enhanced weight loss associated with RYGB.

Quantitative effects of low-dose dopamine on urine output in oliguric surgical intensive care unit patients.

Objective:To quantify the magnitude and time course of the effect of low-dose dopamine (2.5 μg/kg/min) infusions on urine output in oliguric patients.Design:A prospective, clinical study.Setting:A surgical intensive care unit (ICU) at a university hospital.Patients:A total of 19 surgical ICU patient

A.S.P.E.N. Clinical Guidelines Nutrition Support of Hospitalized Adult Patients With Obesity

BACKGROUND Due to the high prevalence of obesity in adults, nutrition support clinicians are encountering greater numbers of obese patients who require nutrition support during hospitalization. The purpose of this clinical guideline is to serve as a framework for the nutrition support care of adult patients with obesity. METHOD A systematic review of the best available evidence to answer a series of questions regarding management of nutrition support in patients with obesity was undertaken and evaluated using concepts adopted from the Grading of Recommendations, Assessment, Development and Evaluation working group. A consensus process, that includes consideration of the strength of the evidence together with the risks and benefits to the patient, was used to develop the clinical guideline recommendations prior to multiple levels of external and internal review and approval by the A.S.P.E.N. Board of Directors. QUESTIONS (1) Do clinical outcomes vary across levels of obesity in critically ill or hospitalized non-intensive care unit (ICU) patients? (2) How should energy requirements be determined in obese critically ill or hospitalized non-ICU patients? (3) Are clinical outcomes improved with hypocaloric, high protein diets in hospitalized patients? (4) In obese patients who have had a malabsorptive or restrictive surgical procedure, what micronutrients should be evaluated?

Erythromycin Facilitates Postpyloric Placement of Nasoduodenal Feeding Tubes in Intensive Care Unit Patients: Randomized, Double-Blinded, Placebo-Controlled Trial

BACKGROUND To determine whether administration of erythromycin (E) could facilitate passage of a nasoenteric feeding tube into the duodenum for postpyloric feedings, this randomized, double-blind, placebo-controlled trial was performed. METHODS Fifty-seven patients were accrued from the surgical intensive care units (ICUs) of a tertiary-care university hospital. Patients enrolled were categorized as to the presence or absence of diabetes mellitus (DM). Those patients without DM were then subdivided into those with normal or depressed mental status. The three groups, normal (NMS), depressed mental status (DMS), or diabetes mellitus (DM), were then randomized independently to receive either E or placebo (P), followed by blind placement of a feeding tube. Tube placement was verified by an abdominal radiograph. RESULTS Overall, the rate of postpyloric placement was 61% (19/31) in the E group, significantly better than 35% (9/26) in the P group (p < .05). In patients with NMS, the success rate with E was improved (64%, 9/14) compared with that with P (9%, 1/11) (p < .0005). In the DMS group, there was a 50% success rate (6/12) with E versus 63% (5/8) with P (not significant [NS]). In the DM group, 80% (4/5) of the patients had placement of the tube in the duodenum with E and 43% (3/7) with P (NS). CONCLUSIONS These data suggest that, overall, E is effective in facilitating placement of a nasoenteric feeding tube into the duodenum in ICU patients. It is clearly beneficial in those patients with normal mental status and may be useful in patients with diabetes mellitus.

Morbid Obesity and Nutrition Support: Is Bigger Different?

Morbid obesity (body mass index >40 kg/m2 or >35 kg/m2 in the presence of an severe-obesity-related comorbid disease) is increasing in frequency in the United States and worldwide. This population has a variety of medical and surgical disorders that result in hospitalizations. It is not unexpected to encounter these patients on the nutrition support service. The obesity comorbid diseases that may increase complications related to nutrition support are present in greater frequency and severity in the morbidly obese population than in the nonobese population. To reduce these potential complications, strategies of hypocaloric nutrition have been advocated for obese patients, and this study focuses specifically on the morbidly obese subset.

A dose-response study of phenylephrine in critically ill, septic surgical patients.

AbstractObjective: To determine the response of haemodynamic and oxygen-transport parameters to phenylephrine in a dose-response fashion in septic non-hypotensive, vasodilated surgical intensive care unit (ICU) patients. Design: Prospective study. Setting: Surgical ICU of a tertiary care, university medical centre. Patients: Ten septic non-hypotensive, vasodilated surgical ICU patients. Interventions: Routine ICU monitoring, including pulmonary and radial artery catheters. Measurements: Haemodynamic and oxygen-transport measurements were taken at baseline and during therapy. Phenylephrine was infused intravenously for 3 h at progressively increasing doses of 0.5, 1.0, 2.0, 3.0, 4.0, and 8.0 μg · kg−1 · min−1 at 30-min intervals. Measurements were taken after each dose. Results: Mean arterial pressure (MAP) and systemic vascular resistance (SVRI) increased linearly with phenylephrine dose. Cardiac index and pulmonary artery occlusion pressures did not change. Statistically significant changes were observed in heart rate, MAP, stroke index, and systemic and pulmonary vascular resistance. Eight patients had a clinically significant increase (>15%) in oxygen consumption (VO2I). Oxygen delivery (D2OI) increased in only three patients. Serum lactate concentrations were unchanged or lower at the end of the study in all eight pateints, who displayed a 15% increase in VO2I. Conclusions: Treatment with phenylephrine increased expected haemodynamic parameters in a linear fashion; however, clinical changes in VO2I occurred at variable doses. Dose-response trials are needed to determine the optimal dose of phenylephrine. Further study is needed to evaluate the clinical effects of phenylephrine in septic patients.